Colibri IMX7 Resistive Touch Problem

Technical Support
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1

Hi ,
We are trying to connect 7" Resistive touch screen display with colibri IMX7(voila plus). when we touch the screen touch pointer are not visible at all. we tried to calibrate touch screen using Xinput_calibrator but we are unable to touch second cross pointer(right corner). when we using ts_calibrate, we can calibrate the touchscreen(value change in /etc/pointercal) but touch screen still not works with toradex desktop. By using ts_test, touch screen is works fine.

root@colibri-imx7:~# ts_calibrate

xres = 800, yres = 480

Took 5 samples…

Top left : X = 3699 Y = 3505

Took 6 samples…

Top right : X = 280 Y = 3498

Took 7 samples…

Bot right : X = 293 Y = 497

Took 5 samples…

Bot left : X = 3738 Y = 499

Took 9 samples…

Center : X = 2002 Y = 1995

811.934631 -0.203957 -0.001766

492.551208 0.000166 -0.126517

Calibration constants: 53210948 -13366 -115 32279836 10 -8291 65536

And We enabled AD7879-1 driver for touchscreen input. still touch input not working.

2

What BSP and hardware version are you using?

I checked with a Colibri iMX7D V1.1C, BSP 2.7 Beta 1 connected to a 5.7" EDT display, it seems to work. When manually start xinput_calibrator, I get the following output:

root@colibri-imx7:~# xinput_calibrator
Calibrating EVDEV driver for "AD7879 Touchscreen" id=7
        current calibration values (from XInput): min_x=4046, max_x=2157 and min_y=3943, max_y=144

Doing dynamic recalibration:
        Setting calibration data: 4009, 2523, 3992, 119
        --> Making the calibration permanent <--
  copy the snippet below into '/etc/X11/xorg.conf.d/99-calibration.conf'
Section "InputClass"
        Identifier      "calibration"
        MatchProduct    "AD7879 Touchscreen"
        Option  "Calibration"   "4009 2523 3992 119"
        Option  "SwapAxes"      "0"
EndSection

Can you check what xinput_calibrator prints in your case?

libts calibration (generated using ts_calibrate) is not used by the X-Server. But since libts calibration worked I guess we can rule out a hardware issue…